For example, in dental treatment, a desired treatment may be performed by cutting a surface layer of a tooth. A medical cutting instrument used during the treatment includes a shank portion gripped by a chuck of a handpiece, and a working portion continuously formed of the shank portion and including a cutting blade which is used to cut a surface layer from an outer circumference to a leading end portion. When a doctor presses a portion to be treated with the working portion while rotating the medical cutting instrument by operating the handpiece, the desired treatment is performed by cutting the surface layer.
In the medical cutting instrument with the above-described configuration, cemented carbide represented by tungsten carbide is generally used for the working portion to ensure a cutting performance with respect to a hard surface layer. However, when the shank portion is also formed using cemented carbide, a problem of increasing the number of hours for processing occurs.
Thus, as the medical cutting instrument, an instrument in which a shank portion is formed of stainless steel or tool steel, and cemented carbide forming a working portion is connected to a front end of the shank portion through butt-jointing is provided. In this way, when different metals such as stainless steel or tool steel and cemented carbide are bonded to each other, a method such as friction pressure welding, resistance welding, or brazing is selectively employed in general.